Studies will be continued to determine the nature of the loss of synaptic transmission in chick's ciliary ganglia after postganglionic axotomy. Specifically, alterations in the quantal parameters associated with release of acetylcholine from the presynaptic terminals will be studied. In addition, morphological studies will be done to determine whether there is any change in membrane recycling in the presynaptic terminals after axotomy by examining uptake of horseradish peroxidase into the terminals. BIBLIOGRAPHIC REFERENCES: Martin, A.R. and Brenner, H.R. Changes in acetylcholine sensitivity of chick ciliary ganglion cells after postganglionic axotomy. The Physiologist 18, 306 (1975).